Multiply and accumulate (MAC) unit is a significant part of the FIR filter design. It is the MAC unit that determines the efficiency of an FIR filter. Many factors like area, power consumption, speed and other key factors are determined by the way the MAC unit is implemented from the programming stage to the final implementation. In this paper, two MAC methods namely, Multiple constant multiplication (MCM) method and Distributed Arithmetic (DA) method are computed using a simulation and synthesis tool and are compared in terms of power consumption to determine the power efficient method. MCM method being a traditional method requires more number of multipliers and adders. Whereas, DA method involves the Look up table to access the filter coefficients continuously, being run by a clock and thereby, results to be a power efficient method.